Re: Search order - why usually two times "Forth"?

From	anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups	comp.lang.forth
Subject	Re: Search order - why usually two times "Forth"?
Date	2015-02-17 12:54 +0000
Organization	Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID	<2015Feb17.135426@mips.complang.tuwien.ac.at> (permalink)
References	<slrnme53rj.1qm.empty.buffersYOU-DONT-WANT-THIS@Ferrycy.localdomain>

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empty-buffers <empty.buffersYOU-DONT-WANT-THIS@gmail.NEITHER-THIS.com> writes:
>I noticed usually ANS-compliant Forth implementations have doubled the first
>position in "Search order", like this (Gforth as example):
>
> order Forth Forth Root     Forth  ok
>
>1. Why is that? In case of need the first position can always be duplicated
>   with ALSO, therefore why it's doubled by default (well, not always, tbh)?

The reason we do it in Gforth is such that programs that contain
idioms like

vocabluary foo
foo definitions
: bar ... ;
forth definitions

(i.e., classic fig-Forth days usage) work.  Programs that use ALSO
still work, and I don't remember ever getting a report of program
failure because of the double occurence of FORTH.

It would have been nice if the Forth-94 was tighter in the description
of the default search order (and what the special parameters of
SET-ORDER mean), but our solution seems to work well anyway.

>2. And does that mean, that in case the word isn't found, text interpreter
>   will search "Forth" vocabulary for the second time, although this one
>   just has been searched with no success?

Depends on the implementation.  In Gforth it does.  One could change
the implementation to avoid that, but we have not yet found the need
to.

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2014: http://www.euroforth.org/ef14/

Thread

Search order - why usually two times "Forth"? empty-buffers <empty.buffersYOU-DONT-WANT-THIS@gmail.NEITHER-THIS.com> - 2015-02-17 00:46 +0000
  Re: Search order - why usually two times "Forth"? "Alex McDonald" <blog@rivadpm.com> - 2015-02-17 09:33 +0000
    Re: Search order - why usually two times "Forth"? empty-buffers <empty.buffersYOU-DONT-WANT-THIS@gmail.NEITHER-THIS.com> - 2015-02-17 10:08 +0000
    Re: Search order - why usually two times "Forth"? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-17 11:07 +0000
  Re: Search order - why usually two times "Forth"? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-17 12:54 +0000
    Re: Search order - why usually two times "Forth"? empty-buffers <empty.buffersYOU-DONT-WANT-THIS@gmail.NEITHER-THIS.com> - 2015-02-17 18:38 +0000
      Re: Search order - why usually two times "Forth"? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-18 11:31 +0000
        Re: Search order - why usually two times "Forth"? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-18 13:16 +0000
          Re: Search order - why usually two times "Forth"? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-18 14:00 +0000
            Re: Search order - why usually two times "Forth"? "Alex McDonald" <blog@rivadpm.com> - 2015-02-18 16:44 +0000
  Re: Search order - why usually two times "Forth"? november.nihal@gmail.com - 2015-02-17 07:13 -0800
  Re: Search order - why usually two times "Forth"? "Elizabeth D. Rather" <erather@forth.com> - 2015-02-17 08:21 -1000
    Re: Search order - why usually two times "Forth"? "Alex McDonald" <blog@rivadpm.com> - 2015-02-17 18:43 +0000
      Re: Search order - why usually two times "Forth"? "Elizabeth D. Rather" <erather@forth.com> - 2015-02-17 11:59 -1000
    Re: Search order - why usually two times "Forth"? hughaguilar96@gmail.com - 2015-02-17 18:30 -0800
      Re: Search order - why usually two times "Forth"? JennyB <jennybrien@googlemail.com> - 2015-02-18 04:01 -0800
        Re: Search order - why usually two times "Forth"? hughaguilar96@gmail.com - 2015-02-18 18:13 -0800
          Re: Search order - why usually two times "Forth"? "HAA" <someone@microsoft.com> - 2015-02-28 11:35 +1100
      Re: Search order - why usually two times "Forth"? "Alex McDonald" <blog@rivadpm.com> - 2015-02-18 12:34 +0000
    Re: Search order - why usually two times "Forth"? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-18 12:28 +0000
  Re: Search order - why usually two times "Forth"? jacko <jackokring@gmail.com> - 2015-02-18 08:49 -0800
    Re: Search order - why usually two times "Forth"? jacko <jackokring@gmail.com> - 2015-02-18 09:04 -0800
      Re: Search order - why usually two times "Forth"? jacko <jackokring@gmail.com> - 2015-02-18 10:17 -0800
        Re: Search order - why usually two times "Forth"? jacko <jackokring@gmail.com> - 2015-02-18 10:20 -0800

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